The background for my desktop and most windows look normal. My icons, some dropdown menus, video and all games big or small have clear alternating blocks in the graphics. I have reinstalled Mac OSX 10.4 (didnt work). Then I upgraded to 10.4.8 (didnt work).downloaded drivers for my ATi Radeon 9600(didnt work). Can someone advise me what to do with this strange problem of mine before I go to the local shops and get charged an arm and a leg to tell me what is wrong and charge me more money to send and get fixed at Apple. I bought it in 2005 mid june and serial numbers dont fall in the series for free repair.http://att.macrumors.com/attachment.php?attachmentid=66302&stc=1&d=1168969024 and picture number 2 ,http://att.macrumors.com/attachment.php?attachmentid=66303&stc=1&d=1168969321 i hope these pictures work thanks.